Twitter says 4 executives are leaving the company

Roetter served as senior vice president of engineering, Schipper was vice president of human resources, Stanton was vice president of social media and Weil was senior vice president of product.

After a long streak of robust growth that turned it into one of the Internet's hottest companies, Twitter's growth has slowed dramatically during the past year-and-half to leave the San Francisco-based company scrambling to catch up with social networking leader Facebook and its 1.5 billion users.

Twitter Inc.'s malaise resulted in the departure of Dick Costolo as the company's CEO last July and ushered in the return of Dorsey, who had been ousted as the company's leader in 2008.